It's only been a week since Miley Cyrus announced her intention to become Mrs. Liam Hemsworth, and already she's defending their commitment.

Eyebrows were raised this week when photos surfaced of a teeny bikini-clad Miley, 19, hanging in a Miami pool with male pal and sometime assistant Cheyne Thomas.

They were also spotted taking a balcony-set smoke break (sidenote: The starlet's nicotine dependence seems counterintuitive given her recent health kick), and Thomas was seen walking with his arm around her shoulder.

The pair's quality time got the Interwebs a-speculating ("Look away now, Liam!" suggested the London Daily Mail), prompting Miley to stick up for their twoo lurve.

"I love my fiancé and he loves me," she tweeted. "All the rest is bulls---. We get to live a life of happiness no one can take that away from us!"

Her declaration was in response to her mom, Tish, who had sighed, "So sad that the nasty tabloids have to make up stories to sell their trashy mags. Cant they just leave these 2 alone and let them be happy."

Miley pointed out that just because she has a diamond ring on her finger, she's still allowed to have a BFF.

"So now because I am engaged I can't have a friend of the opposite sex?" she fumed. "Can't have a friend help me out while I'm working alllll day? #dumb."

The starlet then zinged, "maybe YOU would have friends too if you'd get your face out the tabloids & start living your own life :) unfortunate."

Concurred Thomas, "Not sure if u guys realize it or not but you can hang out with ur friend and look happy and be having fun..there's nothing wrong with that.."

Before heading to Miami to work on her new album, Miley visited Liam on the New Orleans set of "Empire State."

A source tells Us Weekly that the actor "totally lit up" when his future missus arrived.

"She pours affection on him," says an insider. "He's a quiet guy and likes the excitement she brings."

That likely includes her taste in unmentionables. While in town, Miley visited a lingerie store and left with several bags of goodies. She soon tweeted then deleted a photo showing her squeezed into a chest-hoisting corset.

"Liam loves that she's a sexy free spirit," shares a spy, with another adding, "Liam's more stable and levelheaded, so he balances her out. He calms her down."